Abstract Body (Do not enter title and authors here): Background: After decades of progress, cardiovascular (CV) mortality among younger US adults is rising, but little is known about how these patterns vary by income.
Objective: To evaluate trends in cardiovascular mortality among working-age US adults by county-level income from 1999-2023.
Methods: We used American Community Survey data to assign US counties to quintiles by median household income (Q1: lowest; Q5: highest). Age-adjusted CV mortality rates (AAMRs) per 100,000 population in each quintile were obtained from CDC WONDER for adults age 25-64 using ICD codes I.00-99 as the primary cause of death. Annual percent changes (APCs) were determined for 1999-2009 and 2009-2019 using inverse variance-weighted log-linear regression models. Differential trends were assessed using interaction terms with Q1 and Q5 as reference groups. Given the short time period around the COVID-19 pandemic, absolute changes in AAMRs between 2019 and 2023 were calculated and compared using two-sample z-tests.
Results: From 1999-2023, cardiovascular mortality rates were consistently higher in lower-income counties (Figure). Between 1999-2009, CV mortality declined in all quintiles, but higher-income counties experienced a greater decline than lower-income counties (Q5 APC -2.8% [-2.9, -2.7] vs. Q1 APC -1.3% ([-1.5,-1.2]; p<0.0001). From 2009-2019, trends reversed and mortality increased for those in the lower income counties (Q1 APC +0.8% [0.5-1.1]; Q2 APC +0.9% [0.7-1.1];), whereas mortality continued to decline in the highest income counties (Q5: APC -0.5% [-0.7, -0.3]). From 2019-2023, CV mortality increased across all income quintiles, but increases were greatest in the lowest-income county (ΔAAMR +9.5 [6.0-13.0]) compared to all other income groups (p<0.05) (Table).
Conclusions: From 1999-2023, income-based disparities in cardiovascular (CV) mortality widened substantially among working-age U.S. adults. Although CV mortality declined across all income quintiles between 1999 and 2009, gains were more pronounced in higher-income counties. This progress stalled and reversed in 2009, with mortality rates rising among adults in the lowest-income counties while continuing to improve in the highest-income counties. From 2019 to 2023, CV mortality increased across all income groups, but the steepest rises occurred in the lowest-income quintiles. These findings highlight the urgent need to address rising CV mortality that is disproportionately impacting low-income, working-age adults.